Crane



Dec. 19, 1967 M.M.MONTGOMERY,JR

CRANE 3 Sheets-Sheet 1 Filed Aug. 1, 1966 H oI NI jm Ll INVENTOR MURRAYM.MONTGOMERY,JR

X ATTORNEYS Dec. 19, 1967 M. MONTGOMERY, JR 3,

CRANE Filed Aug. 1, 1966 3 Sheets-Sheet 2 My, "4 g ATTORNEYS i. I MURRAYM. MONTGOMERY,JR.

Dec. 19, 1967 M. M. MONTGOMERY, JR 3,358,854

CRANE Filed Aug. 1, 1966 3 Sheets-Sheet 3 FIG 7 INVENTOR. MURRAY M.MONTGOMERY, JR

ATTORNEYS United States Patent 3,358,854 CRANE Murray M. Montgomery,Jr., Oakland, Calif., assignor to Matson Navigation Company, SanFrancisco, Calif., a corporation of California Filed Aug. 1, 1956, Ser.No. 569,434 6 illaims. (Cl. 214-15) This invention relates to cranes,generally, and more specifically to the type installed on a ship, andwhich crane includes a horizontally disposed boom extending thwartwiseof the ship supported from a position within the confines of the outlineof the ship to a position projecting outwardly from one side or theother of such ship. The boom, in turn, normally supports a trolleymovable thereon longitudinally thereof and which trolley includeshoisting means for engaging and supporting a load.

The outreach of the boom is the distance the boom is adapted to projectoutwardly from a side of a ship, and where a single boom has heretoforebeen used, its outreach has a direct relation to the width of the shipat the point where the boom is positioned for the reason that the boomis preferably of maximum length permitting sea storage.

Heretofore, in order to obtain an increased outreach, a plurality oftelescopically related booms have been used in side-by-side relation orone over the other. This invention provides for additional outreach fora single boom.

The reference herein to a single boom relates to booms that may compriseseveral connected boom members, which are normally in parallel, spaced,side-by-side relation and constitute the sole support for the loadcarrying trolley, as distinguished from multiple booms extensiblerelative to each other in the direction of their movement orlongitudinally of the booms.

One of the objects of this invention is the provision of means forincreasing the horizontal outreach of a single trolley-supporting boomat each of two opposite sides of a ship, or supporting structure, beyondthat heretofore accomplished. Another object of the invention is theprovision of a single, horizontally disposed boom, and a trolleythereon, actuatable for simultaneous movement of the boom and trolleylongitudinally of the boom to each of two opposite directions greaterdistances relative to a stationary support on which said boom ismounted, than heretofore.

An added object is the provision of a stationary support for supportinga horizontally disposed trolley-supporting boom for movement of thelatter longitudinally thereof in opposite directions projecting fromeither one side or the other of said support, upon said movement in onedirection or the other, and means on said support movable in saidopposite directions to fixed points of securement to said support, andoperably connected to said boom, for increasing the outreach of saidboom to one side or the other of said support according to the positionof the point of securement of said means to said support.

A still further object of the invention is the provision of a singlehorizontally disposed, trolley-supporting boom supported thwartwise on aship for movement of the boom longitudinally thereof to positionsprojecting from one side or the other of the ship, and a control membermovable to different positions for increasing the outreach of the boomfrom one side or the other of the ship, and which boom, trolley andcontrol member are actuatable for their said movement from a singlesource of power.

Other objects and advantages will appear in the description anddrawings.

In the drawings:

FIG. 1 is a diagrammatic top plan view of a ship having a pair of cranesthereon, one being a conventional crane positioned at a pointintermediate the bow and stern portions of the ship at a point ofapproximately the maximum width of the ship, and the other being a craneembodying the present invention, and positioned in the bow portion, bothcranes being shown in maximum extended positions from the starboard sideof the ship and with their trolleys positioned over a dock at theoutermost end of each crane.

FIG. 2 is diagrammatic enlarged view of a conventional crane of the sametype as the one embodying the present invention, the crane being viewedfrom the foreside, and broken lines indicate the projecting portion ofthe boom when in maximum extended position from the starboard side of aship.

FIG. 3 is a view similar to that of FIG. 2 showing a crane incorporatingthe present invention, and which crane includes a boom in full line instowed position with broken lines indicating the projecting portion ofthe boom when in maximum extended position from the starboard side of aship.

FIG. 4 is a diagrammatic view similar to that of FIG. 3 showing amodified form of the invention shown in FIG. 3.

FIG. 5 is a simplified vertical part cross-sectional and partelevational view taken through a crane and the portion of the ship inwhich the crane is supported along approximately line 5-5 of FIG. 3 toshow the relationship between the boom, ship and trolley and the boomactuating means. The parts of the ship are diagrammatic and greatlysimplified to avoid confusion.

FIG. 6 is an enlargement of a portion only of the structure shown inFIG. 5 taken generally along line 66 of FIG. 5.

FIG. 7 is a fragmentary simplified top plan view of the shuttle deviceof the present invention, broken in Width to accommodate the view of thesheet, and showing the supporting means for the shuttle device.

FIG. 8 is a fragmentary enlarged top plan view of a portion of the craneshowing one connection between one end of the chain for driving the boomand an end cross member at one end of the boom.

A brief reference to FIG. 1 illustrates one problem that is solved bythe present invention, although the advantage of a single boomarrangement providing for an additional outreach at either of theopposite sides of a ship over conventional single boom structure ishighly desirable where the present invention is substituted forconventional single boom structure.

In FIG. 1 a ship is generally indicated at 1, which ship has the usualconverging opposite sides at the bow. A dock 2 is along the starboardside of the ship, the latter being in unloading or loading relation tothe dock, the ship normally being spaced from the dock, as indicated.

A conventional horizontally disposed boom is shown at 3 (FIG. 1) infully extended position with its projecting end 4 extended over the dock2 so that the usual trolley 5 thereon will be in a position to deposit aload onto the dock or to pick up a load, when the trolley is at theouter end of said projecting end.

A power driven pinion 6 (FIG. 2) on the longitudinal centerline of theship engages a rack 7 on the boom for racking the latter in and out ofthe ship an equal distance to either side of the latter. In order toproject an adequate distance from either side of the ship, the length ofthe boom is approximately equal to the width of the ship at the locationof the boom to enable sea stowage of the latter within the ship.

The distance between the sides of the ship in the bow portion issubstantially less than the distance at boom 3, due to the convergenceof said sides, making it impossible to use the boom of FIG. 3 in the bowportion and still provide sea stowage for the boom. A boom of thepresent invention is generally indicated at 8 in FIG. 1 which boom,although substantially shorter than the boom 3 in FIG. 1, is shown infully extended position so that it outer end 9 projects over the dock adistance adequate to deposit a load onto clock 1 in a position of safetyequal to that of the boom3. The present invention enables the boom 8 toextend the same distance from the opposite side of the ship it the dockis on the port side, as will later be explained more in detail.

Where the boom structure of the present invention is installed amidship,or in the position of boom 3, it would be equal to the length of boom 3,and the outreach would be considerably greater in that position than theoutreach of boom 3. In FIG. 3, for example, boom 8 is the same length asboom 3, in order to clearly show the additional outreach where boom 8 isof the same length as that of conventional boom 3.

The trolley in FIG. 2 is connected at one of the ends of cables 10 thatextend oppositely outwardly of the trolley to the ends of the boom 3 andover pulleys 11 on said latter ends, and then over the boom and back toa stationary member 12 on the ship.

In FIG. 2, boom 3 is shown as having wheels 13 that support it formovement within passageway 14 below the upper deck, which passageway isnormally closed at its open ends at the opposite sides of the ship bythe usual doors (not shown) when the boom is stowed within the latter,and when the doors are open the boom is adapted to be projected toeither side of the ship an equal distance.

While the illustrations show booms that are shown and described as beingwithin a passageway within a ship, it is obvious that the booms may besimilarly positioned on a gantry above the deck for moving each of thebooms longitudnally of the ship to difi'erent positions over differenthatches in the upper deck, as is customary in the ship buildingindustry, and in which case the booms, trolleys etc. would be the sameas described, except supported on the gantry, and whatever is describedas being in fixed positions on the ship would be in fixed positions onthe gantry.

In the conventional arrangement as shown in FIG. 2, the trolley 5 ispositioned centrally between the ends of the boom when the latter isstowed on the ship, and upon rotation of pinion 6 in one direction theboom 3 will be racked to the broken line position 15, and the trolley 5will be automatically moved to the outer end of the outwardly projectingportion of the boom when the inner end of the latter is adjacent tofixed point 12 where cables 9 are deadended. The fixed member 13 definesthe limit of outward movement of the boom, and the travel of the trolleyis limited by cables 10 to half the length of the boom.

Referring to FIG. 3, the boom 8 of the present invention issubstantially the same as boom 3 in FIG. 2, and is supported on rollers16 (FIGS. 3, 5) for movement thwartwise of the ship in passageway 17.The latter also extend thwaitwise of the ship and its ends are normallyclosed by the usual doors (not shown) that may be opened for projectingthe boom outwardly of one side or the other of the ship.

A trolley 13 (FIGS. 3, 5) corresponding to trolley 5, is supported onboom 8 for movement longitudinally of the latter, which trolley maycarry the usual load carrying or engaging means and the means forhoisting and lowering such load carrying or engaging means.

A chain 19 (FIGS. 3, 5, 7, 8) is connected at one end 20 thereof to theright end of boom 8, as seen in FIGS. 3, 8, and the other end of thechain is connected to the op posite end of the boom at 21.

A shuttle member generally designated 24 (FIGS. 3, 5, 7) is horizontallymovable on horizontally elongated shuttle supporting means 25 that, inturn, extends parallel with boom 8 to predetermined distances toopposite sides of the longitudinally extending centerline of the ship,or predetermined distances to opposite sides of a point centrallybetween the ends of the boom 8 which the latter is stowed.

This shuttle member 24 rotatably supports a pair of sprocket wheels 26,27 (FIGS. 3, 7) that are in horizontally spaced relation and in the samevertical plane as chain 19 i disposed.

A pair of sprocket wheels 28, 29 (FIGS. 3, 5) are rotatably supported ona fixed portion of ship 1 above boom 8 and in the same plane as sprocketwheels 26, 27. Said wheels 28, 29 are horizontally spaced apart and arepositioned at points adjacent to the opposite ends of the shuttlesupporting means 25. I

A power driven sprocket wheel 30 is positioned in the same verticalplane as wheels 28, 29 at a fixed point above sprocket wheels 28, 29,and wheel 30 is operably connected with any suitable source of power 33for being driven thereby. Also rotatably supported at horizontallyspaced fixed points below said sprocket wheel 30 is a pair of adjacentlypositioned sprocket wheels 34, 3-5 (FIGS. 3, 5).

The length of chain 19 extending from point 20 at the right-hand end ofboom 8, as seen in FIG. 3, extends horizontally over boom 8 to sprocketwheel 26, and then upwardly between sprocket wheels 26, 27 (FIGS. 3, 5)and in engagement with the former and back to sprocket wheel 28 (FIG. 3)and around the latter in engagement therewith to the upper side or" saidwheel 28. From wheel 28, chain 19 extends back to sprocket wheel 3 andupwardly between sprocket wheels 34, 35 in engagement with wheel 34, andover power-driven sprocket wheel 39 in engagement with the latter, andthen again downwardly between wheels 34, 35 and in engagement with wheel35. From wheel 35 the chain extends horizontally to and over sprocketwheel 29, and then back to and downwardly between sprocket wheels 26, 27(FIGS. 3, 5) in engagement with the latter. From sprocket wheel 27 thechain extends to the point 21 at the end of boom 8 that is opposite topoint 20 and where it is deadended on the boom.

By this arrangement it is seen that upon driving the sprocket wheel 30clockwise as seen in FIG. 3, and with the shuttle member 24 locked inplace at the left end of the shuttle support 25, the boom 8 will bedriven to the left out of the open end of passageway 17 in the side ofthe ship to the extended dot-dash line position 37. In this position, itis apparent from a comparison between the dot-dash line position 15 inFIG. 2 and position 37 in FIG. 3, that the boom will project from theside of the ship in FIG. 3 farther than in FIG. 2 by a distance equal tothe distance between the shuttle slide member 24 and the centerline ofthe ship. Also the boom will project from the opposite side of the shipthe same added distance upon movement of the shuttle member 24 to theright as seen in FIG. 3 to the opposite end of the shuttle support 25upon counterclockwise rotation of the sprocket wheel 30.

The trolley 18 is connected to one end of the corresponding ends of apair of cables 38 (FIGS. 3, 5, 6) each of which substantiallycorresponds to cable 10 in FIG. 2, and which cables 38 extend overpulleys 39 on the end of the boom that is adjacent to point 20, and frompulleys 39 back and over pulleys 4,0 that are at the opposite end of theboom. From pulleys 4%, cables 38 extend to and are connected withtrolley 18. The cables 33, 40 extend below and adjacent to the ends ofthe shuttle device that are adjacent to the sides of passageway 17.

By the above arrangement, upon movement of the boom 8 to the left, asviewed in FIG. 3, the trolley 18, at the start and when the boom isstowed within the ship, will be positioned at a point spaced frompulleys 46 a distance substantially equal to twice the distance the boomprojects when in broken line position 37, and the shuttle member 24 andtrolley will be spaced at opposite sides of a point centrally betweenthe ends of boom 8.

The shuttle member is releasably locked to a stationary part of the shipat either end of its movement on each of the supports 25 by a lockingpin 41 (FIGS. 3, 5, 6) that extends through a pin support in the deck ofthe ship and into a recess in the shuttle slide, as will later be shownmore in detail.

The boom itself may be locked in a stowed position by means of aremovable pin 42 (FIG. 5) that may extend through an opening in one sideof the passageway in which the boom is positioned, and into a hole orrecess in the boom.

In order to move the shuttle slide from one end of the shuttle supportto the other, for projecting the boom its maximum distance out of theside of the ship opposite to the one indicated in FIG. 3 it is onlynecessary to lock the boom in its stowed position by pin 42, and unlockthe shuttle slide by removal of pin 41. Upon actuating power sprocket 30counterclockwise, as seen in FIG. 3, the shuttle member 24 will be movedto dotted line position 43 and the trolley will be automatically movedto dotted position 44. The shuttle member will then be locked againstmovement and the boom will be unlocked to enable the boom and trolley tobe projected from the port side of the ship to a position correspondingto the position 37, but at said port side.

With the arrangement described, a single power actuated means is adaptedto move the single boom, trolley and shuttle member, which is anadvantage, but the advantage of obtaining the added outreach of a singleboom at opposite sides of the ship providing means for varying the deadends of the trolley actuating chain, is an important advantageindependently of the boom actuating arrangement.

FIG. 4 is a diagrammatic view that shows a boom 45, and a shuttle member46 supported on a shuttle support 47 for movement of the shuttle memberto opposite ends of the support 47 where it may be locked by lockingmeans 48 corresponding to the locking pin 41. A trolley 49 is supportedon the boom for movement on the latter longitudinallyv thereof. The boomis supported for movement longitudinally thereof in the same manner asboom 8 and cable 50 corresponds to cable 38 for moving the trolley uponlongitudinal movement of the boom 45. Cables 50 extend over the pairs ofpulleys 53, 54 on the respective ends of boom 45 and are connected toone of their ends to the trolley and at their opposite ends to theshuttle 46 as described for cables in FIG. 2.

The shuttle 46, in FIG. 4, carries sprocket wheels 55, 56 that aresimilar to sprocket wheels 34, 35 in FIG. 3, and a power driven sprocketwheel 57 is on the shuttle 46 in a position above and between sprocketwheels 55, 56. A chain 58 is threaded around sprocket wheels 55-57 inthe manner in which chain 19 is threaded around wheels 30, 34, 35 andwhich chain 58 is secured at one end to one end 59 of the boom while theother end of the chain is secured at 6!) to the opposite end of theboom.

Said shuttle member 46 may carry the power and driving means 61 fordriving the shuttle member from one end of the support 47 to the otherend, instead of the driving means being at a fixed point on the ship, asdescribed for FIG. 3. This is the principal distinction between thearrangement in FIG. 3 and that of FIG. 4.

To describe boom 8 more in detail, said boom may comprise a pair ofhorizontally elongated, parallel, horizontally spaced boom members 63(FIGS. 5, 6) respectively disposed along the opposite sides ofpassageway 17, and below the deck 64. The wheels 16 are on each of theboom members, and are supported between vertically spaced lower andupper horizontally extending rails 65, 66 (FIG. 5) that are secured tofixed portions 67 of the ship along the sides of the passageway 17, saidwheels being supported on the lower tracks 65. Said boom mem bers 63 maybe connected by any suitable cross frame members 68 (FIG. 5), positionedbetween corresponding ends of the pair of boom members 63 and at pointsintermediate said ends, and the pairs of pulleys 39, 40 may be carriedby end cross frame members 68 (FIG. 6), and one of the correspondingends of each of said cables 38 is connected with turnbuckle 69 (FIG. 6)while the other end is connected with turnbuckle 70. Turnbnckles 69, 70,in turn, are each connected to a downwardly projecting portion 71 ofeach end frame member 72 of the shuttle member 24 and extend oppositelyfrom said portion. The other end of each cable 38 is connected with aportion 73 that is rigid with the trolley 18 (FIG. 6).

The shuttle member 24 comprises a pair of horizontally disposed framemembers 74, 75 (FIGS. 5, 6, 7) that are spaced apart in side-by-sideparallel relation and that extend between the boom members 63, but shortof the latter and at a level adjacent to the upper sides thereof.

The shuttle support 25 comprises a pair of opposedly openinghorizontally extending channel members 76 which are rigid with portions77 that, in turn, are fixed on ship 1 below deck 64. Channel members 76are parallel with boom members 63, and slide elements 78 at the ends ofthe shuttle frame members 74 extend into the open sides of the channelmembers and are slidable longitudinally thereof (FIG. 7).

The shuttle frame members 75 of the pair thereof are connected by crosspieces 79 (FIG. 7) and each of these pieces 79 has a pair of upwardlyprojecting keepers 80 rigid therewith, which keepers are spaced apart(FIG. 7) to provide a space 81 between them to receive the lower end ofa locking pin 41. Locking pin 41 (FIG. 6) is vertically movable in avertical barrel or sleeve 83 extending through and rigid with deck 64 sothat its lower end will be held between keepers 80. A locking pin is ateach end of the shuttle support for releasably locking the the shuttlemember in the full line position shown in FIG. 3 or in the dottedposition 43 (FIG. 3).

Intermediate the sides of the shuttle member, or at a pointapproximately intermediate the boom members 63,

the pair of sprocket wheels 26, 27 are rotatably supportedbetween framemembers 82 (FIGS. 5, 7) and at a level above said sprocket wheels, atpositions adjacent to the limits of travel of the shuttle member 24, arethe sprocket wheels 28, 29, which wheels are supported by members rigidwith the deck 64.

The shuttle member 24 is limited in its movement between the ends ofchannel members 76 by stop elements 84 (FIGS. 6, 7), which are adaptedto be engaged by elements 85 rigid with the shuttle member.

The sprocket wheel 30, as already explained, is above deck, in thepresent instance, in machine house 86 (FIG. 5), in which house the powermeans 33 is located, and a tunnel housing 87 covers the portions of thechains 19 that may be above deck,

Deck 64 is formed with a slot covered by the tunnel housing extendingsubstantially the length of the travel of the shuttle member to enablemovement of said shuttle member between the limits provided.

An upwardly opening horizontally elongated channel member 88 (FIGS. 5,7) extends between the ends of the boom 8 parallel with andapproximately midway between the boom members 63 to provide a trough inwhich the upper run of chains 19 is slidably supported. Said chain isindicated in FIG. 8 as being a double chain and the sprocket wheels overwhich it extends are double sprockets, although it is to be understoodthat the invention is not restricted to such chain.

The connection between the ends of said chain and each of the ends ofthe boom 8 are seen in FIG. 8 in which each connection comprises anexternally threaded bar 89 extending through plates 90 that are rigidwith the ends of channel member 88, the latter being rigid with endcross members 68 of the boom. Nuts 93 are on the outwardly projectingend of each bar 89 and the inner end of each bar is formed with a head94 to which the end of chain 19 is pivotally connected. A pair of coverplates 7 95 rigid with the end of channel member 87 may partially coverthe end of the chain and head 94.

In operation, assuming loading or unloading of the ship is at thestarboard side and the single boom 8 is fully within the ship, the door(not shown) closing the starboard end of the passageway 17 is opened.The boom is then unlocked by retraction of one or more pins 42.

If the operation is one for loading the ship, the sprocket wheel 36 isactuated by powder means 33 for rotating said sprocket wheelcounterclockwise as viewed in FIG. 3, and the boom will be moved to theleft through the open end of passageway 17 to any desired distance up tothe limit permitted by the position of the shuttle member 24, or to thebroken line position 37 of FIG. 3. This assumes that the shuttle memberis in the full line position shown in FIG. 3 or spaced from the centerline of the boom to the side thereof to which the boom is to beprojected.

Should the trolley be one that is self-powered independently of thepower source 33, the trolley may be moved along the boom to whateverdistance may be desired. In the drawings, however, the arrangement ofcables 38 will effect a simultaneous movement of the trolley with theboom, but at twice the rate of movement of the boom, so that the trolleywill reach the outer end of the boom at the same time as the latterreaches its outermost position.

Whether the crane is within the ship or on a gantry, the trolley 18 mayalways be moved to a position for lowering the load into the hold or fortaking a load out of the ship through the hatch or opening in any deckat the boom. It should also be noted that, in the present instance, agreater advantage in loading and unloading is provided, since thetrolley may be moved by the same power means as drives the boom, asubstantially greater distance within the ship than heretofore,thwartwise of the latter, without projecting the boom to the side of theship opposite to the loading or unloading side thereof.

As has already been mentioned, the shuttle device or member 24 may beshifted from the position indicated in full line in FIG. 3 to thedotted-line position 43 for maximum extension of the boom to the portside of the ship by locking the boom stationary by pin or pins 42 andunlocking the shuttle device by removal of pin or pins 41 and actuatingthe sprocket wheel 30 (FIG. 3) in a counterclockwise direction until theshuttle device is in the dotdash line position 43, where it can belocked to a stationary part by pin 41, after which the boom is againunlocked.

The trolley 18 will now be at the opposite side of the centerline of theship in the dotted line position 44, and after opening the port sidedoor of passageway 17 and driving sprocket wheel clockwise, the boom andtrolley 18 will be projected to the port side of the ship to the samedegree as indicated by the broken line position 37.

It is to be understood that the above detailed description is not to beconsidered limiting, and that changes and modifications may be made thatcome within the spirit of the invention and within the scope of theappended claims.

Also, it should be noted that while the claims refer to a pair of cablesdead ended at one of their ends on the trolley and at their oppositeends on the shuttle member, it is to be understood that a continuouscable may be clamped along its length to the trolley or to the shuttlemember for dead ending the lengths of the cables between the trolley andshuttle member, and the claims are intended to cover such structure.

Many different arrangements may be provided for moving the boom, butwhere the power means is above the passageway 17 as in FIG. 3, less headroom is required Within the passageway than where structure such as inFIG. 4 is used.

I claim:

1. In a crane that includes a boom support structure, a horizontallyelongated boom supported on said boom support structure for movement ofsaid boom longitudinally of the latter in opposite directions from apredetermined retracted position, a load trolley mounted on said boomfor reciprocable movement thereon longitudinally thereof, a pair ofsheaves respectively on opposite ends of said boom, a pair of cablesdead ended at one of their ends on said trolley and respectively reevedover said sheaves and dead ended at their opposite ends on a member onsaid boom support structure, the improvement that comprises:

(a) member-supporting means supporting said member on said boom supportstructure for movement from a point on said boom support structureadjacent to and intermediate the ends of said boom when the latter is insaid retracted position to an offset position between said one end ofsaid boom and said point;

(b) member-locking means for releasably locking said member-supportingmeans stationary relative to said boom support structure at saidoperative position, to thereby provide a greater outreach of said boomand trolley in the direction in which said member is offset than whensaid member is at said point, upon movement of said boom relative tosaid member in said last-mentioned direction.

2. In a structure as defined in claim 1,

(0) power means operably connected with said boom for moving said boomin said one direction from said retracted position and back again.whereby said load trolley will automatically be moved simultaneouslywith said boom in the direction of movement of said boom;

(d) means connecting said power means with said member for moving saidmember from said point to said ofifset position by said power means, andvice versa, when said member-locking means is released to enablemovement of said member on said membersupporting means from said offsetposition to said point, and when said boom is locked in said retractedposition against movement thereof, and

(e) boom locking means for releasably locking said boom in saidretracted position.

3. In a structure as defined in claim 1,

(c) said boom including a pair of parallel horizontally spaced boommembers extending longitudinally of the boom in side-by-side relationand cross pieces rigid therewith connecting said boom members at theirends;

(d) means including an elongated flexible element con nected with saidboom for moving said boom in said one direction from said retractedposition and back again, said flexible element being disposedsubstantially centrally between said boom members parallel therewith andconnected with said end pieces;

(e) power actuated means connected with said element for moving thelatter longitudinally thereof in opposite directions to thereby movesaid boom in said one direction from said retracted position and backagain;

(f) said pair of sheaves being at opposite ends of one of said boommembers and a second pair of corresponding sheaves on said boom at theopposite ends of the other of said boom members, and a second pair ofcables reeved over said second pair of sheaves dead ended at one oftheir ends on said trolley and dead ended at their opposite ends on saidmember;

(g) said member including means for dead ending the ends of said secondpair of cables that are opposite to the ends dead ended on said trolleyat points adjacent to the boom member having said second pair of sheavesat its ends.

4. In a crane that includes a boom support structure, a horizontallyelongated boom supported on said boom support for movement of said boomlongitudinally of the latter in opposite directions from a predeterminedretracted position, a load trolley mounted on said boom for reciprocablemovement thereon longitudinally thereof, a pair of sheaves respectivelyon opposite ends of said boom, a

pair of cables dead ended at one of their ends on said trolley andrespectively reeved over said sheaves and dead ended at their oppositeends on a member on said boom support structure, the improvement thatcomprises:

(a) member-supporting means supporting said member on said boom supportstructure for movement from a fixed point on said boom supportingstructure substantially centrally between the ends of said boom when thelatter is in said retracted position, to offset positions spacedlongitudinally of said boom to opposite sides of said point;

(b) member-locking means for releasably locking said member stationaryrelative to said boom support structure at each of said offset positionsof said member thereby providing a greater otureach of said boom andtrolley to one side or the other of said fixed point according to theside to which said member is oifset than when said member is at saidpoint, and

(c) boom-moving means operatively connected with said boom for moving itlongitudinally thereof in opposite directions.

5. In a structure as defined in claim 4,

(d) boom-locking means for releasably locking said boom stationaryrelative to said boom support structure when said boom is in saidretracted position;

(e) said trolley being on said boom in a position ofiset longitudinallythereof to the side of said point opposite to the ofiset position ofsaid member when said boom is in said retracted position;

(f) said boom-moving means including power means for moving said memberon said member-supporting means from one of said offset positions to theother upon releasing said member-locking means and lock-ing said boomstationary by said boom-locking means and then actuating said powermeans for moving said boom were the latter not held by said boom lockingmeans.

6. In a structure as defined in claim 4,

(d) said boom support structure including stationary rigid shipstructure along the sides of a passageway within a ship extendingthwartwise of the latter with the ends of said passageway at oppositesides of the ship for projecting the boom from one or the other of saidsides;

(e) said boom being wholly enclosed within said passage way extendinglongitudinally of the latter when in said retracted position with saidfixed point being substantially on the centerline of said ship, andmeans rigid with said ship along opposite lateral sides of saidpassageway supporting said boom for its movement, and supporting saidmember-supporting means for movement of said member in the samedirections as said boom;

(f) said element being a sprocket chain, and sprocket wheels in drivingengagement with said chain, one of which sprocket wheels is said poweractuated means;

(g) said member-locking means and said boom-locking means being pinscarried by said boom supporting structure movable into and out ofpositive locking engagement with said member and with said boom.

References Cited UNITED STATES PATENTS 2,456,104 12/ 1948 Anderson214-15 2,541,893 2/1951 Speer 212-15 3,317,058 5/ 1967 Kummerman 21274ANDRES H. NIELSEN, Primary Examiner.

1. IN A CRANE THAT INCLUDES A BOOM SUPPORT STRUCTURE, A HORIZONTALLYELONGATED BOOM SUPPORTED ON SAID BOOM SUPPORT STRUCTURE FOR MOVEMENT OFSAID BOOM LONGITUDINALLY OF THE LATTER IN OPPOSITE DIRECTIONS FROM APREDETERMINED RETRACTED POSITION, A LOAD TROLLEY MOUNTED ON SAID BOOMFOR RECIPROCABLE MOVEMENT THEREON LONGITUDINALLY THEREOF, A PAIR OFSHEAVES RESPECTIVELY ON OPPOSITE ENDS OF SAID BOOM, A PAIR OF CABLESDEAD ENDED AT ONE OF THEIR ENDS ON SAID TROLLEY AND RESPECTIVELY REEVEDOVER SAID SHEAVES AND DEAD ENDED AT THEIR OPPOSITE ENDS ON A MEMBER ONSAID BOOM SUPPORT STRUCTURE, THE IMPROVEMENT THAT COMPRISES: (A)MEMBER-SUPPORTING MEANS SUPPORTING SAID MEMBER ON SAID BOOM SUPPORTSTRUCTURE FOR MOVEMENT FROM A POINT ON SAID BOOM SUPPORT STRUCTUREADJACENT TO AND INTERMEDIATE THE ENDS OF SAID BOOM WHEN THE LATTER IS INSAID RETRACTED POSITION TO AN OFFSET POSITION BETWEEN SAID ONE END OFSAID BOOM AND SAID POINT; (B) MEMBER-LOCKING MEANS FOR RELEASABLYLOCKING SAID MEMBER-SUPPORTING MEANS STATIONARY RELATIVE TO SAID BOOMSUPPORT STRUCTURE AT SAID OPERATIVE POSITION, TO THEREBY PROVIDE AGREATER OUTREACH OF SAID BOOM AND TROLLEY IN THE DIRECTION IN WHICH SAIDMEMBER IS OFFSET THAN WHEN SAID MEMBER IS AT SAID POINT, UPON MOVEMENTOF SAID BOOM RELATIVE TO SAID MEMBER IN SAID LAST-MENTIONED DIRECTION.